Stabilized soap composition



Unite rates STABILIZED SOAP COMPOSITION Victor C. Fusco, Baltimore, Md., and Richard 'C. Harshman, Kenmore, N.Y., assignors to Olin Mathieson Chemical Corporation, a corporation of Virginia No Drawing. Filed June 2, 1955, Ser. No. 512,863

21 Claims. (Cl. 252-107) This invention relates to improved compositions containing fatty acid radicals including fats, oils, soaps and soap products. More particularly, it relates to improved soap compositions containing phenolic bactericides. Still more particularly, this invention relates to such bactericidal soaps containing hydrazine salts of organic acids as Stabilizers of the phenolic soap compositions.

The tendency of soaps to discolor and become rancid in storage or use is well known. These effects have been attributed to a variety of causes including the manufacture of soaps from fats and oils which themselves tend to become rancid. It is also believed that minor metallic contaminants particularly iron and copper in minute amounts accelerate the formation of oxidation products resulting in undesirable odor or discoloration. These effects may appear in various forms of soap including bar soap, powdered soap, granulated soap and spray-dried soaps in the form of beads.

Soaps in liquid form, usually potassium soaps, are more difiicult to stabilize in these respects than sodium soaps and many of the proposed stabilizers are generally unsatisfactory for the production of stable potassium soaps or blends containing substantial amounts of potassium soaps.

The principal method of attack on this problem has been to add various anti-oxidants or other stabilizers to soap compositions in an effort to overcome these effects. Many of the suggested inhibitors afford a partial solution, for example, in inhibiting odor formation without affecting or even deleteriously affecting color stability.

The problem of soap stabilization has more recently been further aggravated by the incorporation of phenolic bactericides in soap. Although phenolic anti-oxidants have been proposed for the stabilization of soap, many are ineffective and some phenolic compounds even accelerate the deterioration. A commonly used phenolic bactericide in soap is 2,2-dihydroxy-3,5,6,3',5,6-hexachlorodiphenylmethane (hexachlorophene). Small proportions, for example, 0.5 percent in soap appear to accelerate color formation. This effect may be masked by the incorporation of yellow coloring matter in the composition so that subsequent yellowing during storage or use is not so obvious. The problem of incorporation of such phenolic bactericides in white toilet soap so far has not been solved. It is important therefore to provide new and improved stabilizers for soap which are effective in the presence of phenolic bactericides.

It has been discovered that soap compositions containing or not containing phenolic bactericides are effectively stabilized by the incorporation therein of minor proportions of hydrazine salts of organic acids. Suitable proportions of these stabilizers are from about 0.05 to one percent by weight, based on the weight of the dry soap.

Suitable hydrazine salts which can be used in accordance with the present invention include the hydrazinium I 2,971,917 Patented Feb. 14, 1961 salts of aliphatic monocarboxylic acids containing from 1 to 18 carbon atoms, such as hydrazinium acetate, hydrazinium propionate, hydrazinium butyrate, hydrazinium valerate, hydrazinium caproate, hydrazinium laurate, hydrazinium myristate, hydrazinium palmitate, hydrazinium stearate, hydrazinium elaidate and the like. The hydrazinium salts of polybasic acids, such as monohydrazinium oxalate, dihydrazinium oxalate, monohydrazinium succinate, monohydrazinium adipate, dihydrazinium adipate, monohydrazinium fumarate, monohydrazinium tartrate, dihydrazinium tartrate, dihydrazinium citrate, monohydrazinium citrate and hydrazinium naphthenate, can be utilized. Also useful are the hydrazinium salts of monobasic aromatic acids, such as hydrazinium benzoate and di-, tri-, and tetrahydrazinium pyromellitate. Hydrazinium salts derived from substituted bydrazines can be used, for example, beta-hydroxyethylhydrazinium stearate, di-(beta-hydroxyethyl)-hydrazinium stearate, unsymmetrical dimethylhydrazinium keryl benzene sulfonate and phenyl hydrazinium oleate, as well as hydrazinium keryl benzene sulfonate. Mixtures of hydrazinium salts, salts of mixed fatty acids or mixtures of the hydrazinium salts with known compatible soap stabilizers may be used.

The stabilizers should not be added at a stage which will result in decomposition, leaching, or deterioration of the stabilizing agent. They can be incorporated in the soap compositions at any convenient step after the saponification. For example, they can be added to the neat soap as made in the kettle in the manufacture of frame soap. In the manufacture of milled soap, it is ordinarily preferable to add the stabilizer to the mixer preceding the milling together with perfume materials and coloring agents if desired. The stabilizer can also be incorporated during the crutching process. The stabilizer can be added conveniently in the form of aqueous solutions since the hydrazinium salts are generally water soluble. Where the salts are viscous liquids, they can be incorporated as such or in aqueous solution. Where the salts are solids, they can be dissolved in water or incorporated as the dry solids, preferably finely divided. Mixing subsequent to the addition of the stabilizer should be sufficient to render the soap composition homogeneous.

The soap product can subsequently be dried and formed into cakes, plates, beads or other forms as desired. In the manufacture of liquid soap compositions the stabilizers can be dissolved in the soap solutions or aqueous solutions thereof when conveniently prepared can be added to the liquid soap composition.

The stabilizers are effective in soaps of various types, including laundry soaps, facial soaps and in soaps subsequently incorporated in cosmetic compositions includ ing tooth paste, face creams and body creams.

The stabilizers of the present invention are also effective in delaying the oxidative deterioration of fatty ma terials generally as well as the soaps for which they are especially suited. Minor proportions of these stabilizers are effective in fats, fatty oils and other esters of unsaturated fatty acids as well as inks, paints, varnishes, enamels and other materials containing them.

Example I A liquid potassium coconut oil soap was prepared by heating a mixture of 420 grams of coconut oil, 300 grams of 36 percent aqueous potassium hydroxide and 1867 grams of water on a steam bath for 16 hours. Sufiicient 2,2'-dihydroxy 3,5,6,3,5,6 hexachlorodiphenylmethane (hexachlorophene) was dissolved in the liquid soap to produce a solution containing 0.5 weight percent of hexachlorophene based on the dry soap weight. To a 50 milliliter portion of the soap solution containing hexachlorophene was added 0.26 gram of hydrazinium glycollate. The same amount of hydrazinium naphthenate was added to another 50 milliliter portion of the soap solution. The hydrazinium glycollate and naphthenate were prepared by mixing one gram mole of anhydrous (95 percent) hydrazine with approximately one gram equivalent of the organic acid.

The two test samples together with a 50 milliliter test sample containing hexachlorophene and a 5'0 milliliter sample without the hexachlorophene were heated in an oven at l00-200 C. for two weeks. Most of the water evaporated from the samples after a few hours of heating. At the end of the heating period, the samples were cooled to 28 C. and diluted to 50 milliliters with water. Any insoluble matter was removed by filtration and the light transmission of the filtrates was determined using a No. 525 Series blue filter in a Fischer electro- These data show that the hexachlorophene adversely affects the color stability of the soap solution and that the two hydrazinium salts materially improve the stability in this respect.

Example II Additional quantities of the same potassium soap solution were used in the following test. Hydrazinium glycollate and hydrazinium naphthenate were dissolved in separate 50 milliliter portions of the soap solution already containing 0.5 weight percent of hexachlorophene based on dry soap weight to make solutions containing 0.5 weight percent of the hydrazinium salt, also based on dry soap weight. A portion of each solution was sealed in a glass ampule and heated in an oven at 80 C. for two weeks. At the end of this time the ampules were cooled, opened and the percent light transmission was measured with a Fischer electrophotometer using a No. 525 Series blue filter. The results shown in the follow ing table were obtained.

These data show that the test procedure was less severe than in Example I where the water was allowed to evaporate and was later replaced. Thus the light transmission of the heated sample Without stabilizer was 87.5 percent of that of the unheated sample, both containing 0.5 percent of the hexachlorophene. The presence of the hydrazine soaps showed a material improvement in color stability of the soap compositions during the test. Two commercial antioxidants were ineffective and even decreased the color stability of the samples.

Example 111 Two 50 gram samples of freshly churned, unsalted butter, one containing 0.5 weight percent of hydrazinium naphthenate dissolved therein, were placed in 250 milliliter glass stoppered Erlenmeyer flasks. To each flask was added a 7 centimeter circle of filter paper torn in small pieces and wetted with one milliliter of water. The flasks were stoppered and placed in an oven at C. for several days. A rancid odor developed in the untreated sample after 3 days but the stabilized sample was still sweet when the test was discontinued after 7 days.

Example IV Blends of soap with several hydrazinium salts were prepared by thoroughly mixing 0.5 part by weight of the salt with 99.5 parts of pure soap stock (essentially the sodium soap of tallow fatty acids) at room temperature. The mixture was pressed into 20 gram bars at 2000 p.s.i.g. Four test bars of each blend and four similar bars prepared from the same soap stock but omitting the hydrazinium salt were stored in an oven at to 104 C. for two weeks. At the end of this time, the light reflected from the surface of the blocks was measured The hydrazinium distearate was prepared by melting stearic acid and admixing one gram mole of anhydrous hydrazine for each two moles of stearic acid and allowing the mixture to cool. Hydrazinium benzoate was prepared by mixing equal moles of anhydrous hydrazine and benzoic acid, each dissolved separately in methanol and removing some of the methanol by distillation. The residue was cooled and the hydrazinium benzoate crystallized. It was filtered and dried. The hydrazinium propionate was prepared by mixing equimolar proportions of anhydrous hydrazine and propionic acid at room temperature.

All of these hydrazinium salts showed improvement in the color stabilization of this soap. The hydrazinium distearate and hydrazinium naphthenate were especially effective.

Various modifications can be made in the procedures of the specific examples to provide other improved soap and soap-containing compositions falling within the scope of our invention. Our invention is generally applicable for the purpose of improving the properties of soaps and soap-containing compositions as those terms are generally understood in the art. In the specific examples, the soaps employed were sodium soaps of tallow fatty acids or a potassium soap of coconut oil fatty acids. Other soaps can be substituted for those specifically used, and our invention comprehends the improvement of soaps and compositions containing them in which the cationic portion is, for example, ammonia, an amine, an alkali metal or an alkaline earth metal, such as sodium, potassium, lithium, calcium, barium, and so forth, as well as magnesium, aluminum, zinc and cadmium. The anionic portion of the soap is generally derived from one or more aliphatic monocarboxylic acids containing from 12 to 18 carbon atoms, such as lauric acid, myris tic acid, palmitic acid, stearic acid, oleic acid, and so forth. The soaps suitable for use in our invention can also be derived in known manner from a wide variety, of naturally-occurring materials or derivatives thereof, including tallow, palm oil, hydrogenated marine oils such as whale oil, coconut oil, palm kernel oil, rosin, tall oil, lard, olive oil, cottonseed oil, peanut oil, soya bean oil, linseed oil, and so forth. Also, various other phenolic bactericides garner? can be substituted for the hexachlorophene used in the examples, among them being hexylresorcinol, cresol, thymol, chlorothymol and guaiacol. Hydrazinium salts may also be incorporated in greases. These are commonly soap-thickened petroleum oils containing lithium, sodium, calcium, aluminum or other metal soaps of various acids including those derived from tall oil, tallow, castor oil or waste fat acids, for example.

We claim:

1. A soap composition consisting essentially of a soap of an aliphatic monocarboxylic acid containing from 12 to 18 carbon atoms and a hydrazinium salt of an organic acid in an amount effective to stabilize the composition against discoloration and undesirable odor formation.

2. A soap composition according to claim 1 in which the soap is a sodium soap.

3. A soap composition according to claim 1 in which the soap is a potassium soap.

4. A soap composition according to claim 1 also containing a phenolic bactericide in an amount eifective to render the soap germicidal.

5. A soap composition according to claim 1 also containing 2,2'-dihydroxy-3,5,6,3',5',6'-hexachlorodiphenylmethane in an amount effective to render the soap germicidal.

6. A soap composition according to claim 1 in which the hydrazinium salt is hydrazinium glycollate.

7. A soap composition according to claim 1 in which the hydrazinium salt is hydrazinium naphthenate.

8. A soap composition according to claim 1 in which the hydrazinium salt is hydrazinium distearate.

9. A soap composition according to claim 1 in which the hydrazinium salt is hydrazinium benzoate.

10. A soap composition according to claim 1 in which the hydrazinium salt is hydrazinium propionate.

11. A soap composition according to claim 1 in which the soap is a sodium soap and in which the hydrazinium salt is hydrazinium glycollate.

12. A soap composition according to claim 1 in which the soap is a sodium soap and in which the hydrazinium salt is hydrazinium naphthenate.

13. A soap composition according to claim 1 in which the soap is a sodium soap and in which the hydrazinium salt is hydrazinium distearate.

14. A soap composition according to claim 1 in which the soap is a sodium soap and in which the hydrazinium salt is hydrazinium benzoate.

15. A soap composition according to claim 1 in which the soap is a sodium soap and in which the hydrazinium salt is hydrazinium propionate.

16. The soap composition of claim 1 in which the hydrazinium salt comprises a minor proportion of the soap composition.

17. The soap composition of claim 1 in which the amount of hydrazinium salt is about 0.05 to 1 percent by weight of the dry soap.

18. The soap composition of claim 4 in which the hydrazinium salt comprises a minor proportion of the soap composition.

19. The soap composition of claim 5 in which the amount of hydrazinium salt is about 0.05 to 1 percent by weight of the dry soap.

20. The soap composition of claim 18 in which the amount of bactericide is at least about 0.5 percent by weight of the dry soap.

21. The soap composition of claim 19 in which the amount of 2,2'-dihydroxy-3,5,6,3,5',6'-hexachlorodiphenylmethane is at least about 0.5 percent by weight of the dry soap.

References Cited in the file of this patent UNITED STATES PATENTS 1,973,724 Perkins et a1. Sept. 18, 1934 2,014,924 Benedict Sept. 17, 1935 2,469,377 Flett May 10, 1949 2,535,077 Kunz et al. Dec; 26, 1950 2,544,772 Audrieth et al. Mar. 13, 1951 2,680,122 Black et a1. Sept. 14, 1951 2,729,690 Oldenburg Jan. 3, 1956 2,730,502 Beaver et al. Jan. 10, 1956 OTHER REFERENCES The Chemistry of Hydrazines, Ogg, Wiley & Sons, N.Y. (1951), pages 226-7. 

1. A SOAP COMPOSITION CONSISTING ESSENTIALLY OF A SOAP OF AN ALIPHATIC MONOCARBOXYLIC ACID CONTAINING FROM 12 TO 18 CARBON ATOMS AND A HYDRAZINIUM SALT OF AN ORGANIC ACID IN AN AMOUNT EFFECTIVE TO STABILIZE THE COMPOSITION AGAINST DISCOLORATION AND UNDERSIRABLE ODOR FORMATION. 